The present invention generally relates to apparatus and methods for aircraft door seals and, more particularly, to apparatus and methods for aircraft door seals using piano type hinges.
It is necessary to seal aircraft doors including those required in-flight operation such as weapons bay doors. Mold line gaps around in-flight operable doors create drag, turbulent flow and sealing problems for aircraft. Compounding the problem there is limited space within a fighter aircraft for the door hinge mechanism. This places a limit on the choice of hinge mechanism and some of the easier to seal hinge mechanisms require maximum space from the bays they are adjacent to. For example, a piano hinge mechanism is the simplest hinge that requires the least amount of space. But the piano hinge requires a hinge cover seal capable of adapting to a door hinge edge travel that requires a longer seal at door closure then when the door is open. As the piano hinged door closes, the hinge cover seal must be able to compensate for the increasing distance between the hinge edge of the door and the door frame. See FIG. 3 for door open and FIG. 4 for closed. This typically results in a complicated, bulky seal or a seal that does not cover the mold line gaps on the hinge side of the door.
One prior art solution uses metal or composite blade seals around the entire door requiring ‘goose neck hinges’, see prior art FIG. 5, to prevent the blade seal adjacent the hinge side of the door from contacting aircraft mold line in the door open position. However, the goose neck hinges require a substantially greater volume than a piano hinge because the hinge linkages are bulky. This takes up valuable space in one or more bays of the aircraft.
Another approach uses the so-called ‘6 bar linkage’ hinge, which again simplifies the problem of sealing by maintaining a relatively constant distance between the door frame and the hinge sealing edge of the door. This simplifies the seal because the hinge cover seal does not need to stretch, just bend, but again this results in a bulkier and more complicated hinge that takes more space from the bays adjacent to it. The ‘6 bar linkage’ hinge and goose neck hinge also place moving links in the bay that must be accounted for in designing the use of the bay.
As can be seen, there is a need for an aircraft door seal that allows for effective sealing around the hinge side of the door and door frame. There is a need for a seal that can be employed with a simple piano hinge mechanism to reduce mechanical protrusions into the bay space of the aircraft. Moreover, there is a need for efficient seal that can be used with aircraft doors including those that are operational in-flight such as weapons bay doors.